Molecular dynamics simulations of the melting curve of NiAl alloy under pressure

Wenjin Zhang,Yufeng Peng,Zhongli Liu

doi:10.1063/1.4876515

Wenjin Zhang, Yufeng Peng + Show 1 more

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https://doi.org/10.1063/1.4876515

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Abstract

The melting curve of B2-NiAl alloy under pressure has been investigated using molecular dynamics technique and the embedded atom method (EAM) potential. The melting temperatures were determined with two approaches, the one-phase and the two-phase methods. The first one simulates a homogeneous melting, while the second one involves a heterogeneous melting of materials. Both approaches reduce the superheating effectively and their results are close to each other at the applied pressures. By fitting the well-known Simon equation to our melting data, we yielded the melting curves for NiAl: 1783(1 + P/9.801)0.298 (one-phase approach), 1850(1 + P/12.806)0.357 (two-phase approach). The good agreement of the resulting equation of states and the zero-pressure melting point (calc., 1850 ± 25 K, exp., 1911 K) with experiment proved the correctness of these results. These melting data complemented the absence of experimental high-pressure melting of NiAl. To check the transferability of this EAM potential, we have also predicted the melting curves of pure nickel and pure aluminum. Results show the calculated melting point of Nickel agrees well with experiment at zero pressure, while the melting point of aluminum is slightly higher than experiment.

Highlights

It is a fundamental issue to investigate the melting behaviors of transition metals and their alloys under high pressure in condensed-matter physics, geophysics and astrophysics, etc
To assess the qualities of the embedded atom method (EAM) potential applied in this work, we have first performed molecular dynamics (MD) simulations for the equilibrium lattice parameters a0 of B2-NiAl at ambient conditions
We note that the results obtained from this EAM potential are in excellent agreement with experimental values.[47]

Summary

Introduction

It is a fundamental issue to investigate the melting behaviors of transition metals and their alloys under high pressure in condensed-matter physics, geophysics and astrophysics, etc. Despite extensive experimental[6,7,8,9] and theoretical[10,11,12,13] studies have been performed on the melting properties of transition metals in the past decade, large discrepancies still exist among their DAC,[6,14,15] SW, and theoretical results.[18,19,20,21] For instance, very recently, Pozzo et al.[13] reported a melting curve of Ni under pressure up to 100 GPa based on ab initio MD calculations They found that the calculated zero-pressure melting temperature is 1637 ± 10 K, which is slightly underestimated compared with the experimental value of 1728 K.9. This again confirms that MD simulations mainly support the shock data,[5,12,23] while the strong

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